Damage from rainfall flooding

Matthieu Spekkers. (Photo: Tomas van Dijk)

Name: Matthieu Spekkers (29)
Nationality: Dutch
Promotors: Professor Francois Clemens and Dr Marie-Claire ten Veldhuis (Civil Engineering and Geosciences, Urban Drainage section)
Subject: Urban flooding due to heavy rainfall
Thesis defense: In 2.5 years

“The Dutch have been fighting against water for ages. One might think that flooding is only caused by water from rivers and seas, but Dutch cities must also regularly deal with flooding problems caused by very heavy rainfall. The water pours into houses because the urban drainage system - sewers for example - cannot handle it. Homeowners are even obliged to insure against this type of flooding. And because this happens a couple of times a year in various places throughout the Netherlands, flooding is causing considerable damage.

My focus is on this kind of flooding, looking for statistical relations between, for example, rainfall and the observed damage. Does the rainfall intensity and volume relate to the amount of damage? I use meteorological information from the KNMI (Royal Dutch Meteorological Institute), as well as claims data from insurance companies.

It’s quite extraordinary that I’m allowed to use insurance data, because insurance companies usually keep such information to themselves, as they are bound by strict privacy rules for their clients and there is intense competition among the various insurance companies. But luckily the insurance companies were willing to share their information with me. The Dutch Association of Insurers provides me with data.
The reason why they are obliging is that they also have many questions regarding the statistical relations I am investigating; for example, they would like to know if climate change will lead to more and higher claims. My research does not incorporate climate change effects, although I might look into that, too. My research results could prove valuable for insurance companies and may also be used to better understand climate change effects.

The results of my current research of rainfall and damage will determine what areas I will investigate in the coming years. I might also try to make comparable statistical relations using the properties of urban drainage systems – the types of sewers for example – or topographical features and flood damage.

I will conduct a detailed case study of Rotterdam, and have a detailed elevation map of that city for this purpose. The Netherlands is relatively flat, but this map shows the heights of all the different objects – even curbs, which can make a difference between being flooded or not. I also have documentation of the different sewer systems in Rotterdam.

I hope that I can also study how flooding caused by heavy rainfall impacts vital infrastructure, like electricity or telephony. There is not much literature and data available on this topic yet, although it is vulnerable to flooding.”